Insights into the Chemical Nature and Formation Mechanisms of Discharge Products in Na–O2 Batteries by Means of Operando X-ray Diffraction

2016 ◽  
Vol 120 (16) ◽  
pp. 8472-8481 ◽  
Author(s):  
R. Pinedo ◽  
D. A. Weber ◽  
B. Bergner ◽  
D. Schröder ◽  
P. Adelhelm ◽  
...  
Keyword(s):  
Chemical Nature ◽  
Formation Mechanisms ◽  
X Ray Diffraction ◽  
X Ray

Photochemische Reaktionen von Übergangsmetall-Organyl-Komplexen mit Olefinen, XVI [1]: Photochemisch induzierte Cycloadditionen von Diphenylacetylen an Tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)mangan / Photochemical Reactions of Transition Metal Organyl Complexes with Olefins, XVI [1]: Photochemically Induced Cycloadditions of Diphenylacetylene to Tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)manganese

1996 ◽  
Vol 51 (10) ◽  
pp. 1473-1485 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Ernst-Christian Koch ◽  
Walter Frank ◽  
Guido J. Reiß
Keyword(s):  
Mass Spectra ◽  
Photochemical Reactions ◽  
Molecular Structures ◽  
Manganese Complexes ◽  
Formation Mechanisms ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray

Upon UV irradiation in THF at 208 K tricarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)- manganese (1) yields solvent stabilized, very reactive dicarbonyl(η5-2,4-dimethyl-2,4-pentadien-1-yl)(tetrahydrofuran)manganese (2), which reacts in situ with one or two molecules of diphenylacetylene (3) and yields four manganese complexes and 1,3-dimethyl-5,6-diphenyl-bicyclo[3.2.1]oct-2-ene-7-one (5), which were separated by HPL chromatography. In addition to tricarbonyl η5-4,6 -dimethyl-1,2-diphenyl-cyclohepta-2,4-dien-1-yl)manganese (4) formed by [5+2]cycloaddition and successive 1,4-H shift, tricarbonyl{ 1′,2′,5′-η-5-methyl-2,3 -diphenyl-5- (2′-methyl-4′,5′-diphenyl-penta-1′,4′-dien-1′,5′-diyl)cyclopent-2-en-1 -one-κ-O}manganese (6) is isolated with a ligand, formed from 2,4-dimethyl-2,4-pentadien-1-yl, two units of 3 and one carbon monoxide. The ligands of tricarbonyl{ 1-4,2′-η-4,6 -dimethyl-1,2-diphenyl-5-(E-1′,2′- diphenyl-vinylen)cyclohepta-1,3-diene}manganese (7), and tricarbonyl{η5-4,6 -dimethyl-1,2-diphenyl-7-(E-1′,2′-diphenyl-vinyl)cyclohepta-2,4-dien-1-yl}m anganese (8) are formed from 2,4-dimethyl-2,4-pentadien-1-yl and of two molecules of 3 each. The crystal and molecular structures of 5 and 6 have been determined by single crystal X-ray diffraction. 5 crystallizes in the triclinic space group P1̅ , a = 992.0(2) pm, b = 996.8(2) pm, c = 1021.0(2) pm, a = 77.67(3)°, β = 61.17(3)°, γ = 88.68(3)°. Complex 6 crystallizes also in the triclinic space group P1̅ ,a = 1023.2(2) pm, b - 1113.8(2) pm, c = 1567.9(3) pm, α = 82.88(3)°, β = 86.93(3)°, 7 = 63.53(3)°. The constitutions of 4, 7 and 8 were elucidated from the IR, NMR and mass spectra. Possible formation mechanisms for the compounds 4-8 are proposed. Complex 7 shows hindered rotations of two phenyl groups with different barriers of energy ΔG≠316 = 68.8 kJ/mol, „ΔH≠ = 67.9 ± 0.7 kJ/mol, ΔS≠ = -2 ± 2 J/mol · K and ΔG≠296 = 60.6 kJ/mol, ΔH≠ = 57.7 ± 1.0 kJ/mol, ΔS≠ = -10 ± 2 J/mol·K due to steric interactions.

scholarly journals ELECTROCHEMICAL INVESTIGATIONS OF THE INTERACTION OF CAFFEINIUM COMPOUNDS WITH POLYANІОNES OF Мо AND W WITH OF 1,3,5 - TRIPHENYL VERDAZYL RADICAL

2021 ◽  
Vol 86 (12) ◽  
pp. 124-133
Author(s):  
Olha Panteleieva ◽  
Kateryna Plyasovskaya ◽  
Olexandr Shtemenko
Keyword(s):  
Concentration Ratio ◽  
Chemical Nature ◽  
Spectrophotometric Analysis ◽  
Model Reaction ◽  
Electrochemical Studies ◽  
X Ray Diffraction ◽  
Active Centers ◽  
X Ray ◽  
Verdazyl Radical ◽  
Cathode Current

The work continues the study on the peculiarities of the interaction of 1,3,7-trimethylxanthine (caffeine) compounds with polyoxometalates of molybdenum and tungsten with the artificial radical of 1,3,5- triphenylverdazyl (TFV). Using the example of a model reaction with the TFV radical, these compounds showed a special antiradical action. Based on the research results, it was found that the nature of the destruction of the radical when interacting with (HСaf)3[PМ12O40]∙6H2O (where М = Мо, W) differs from most known systems, which are characterized by a mechanism of disproportionation. The data obtained confirmed the previously made assumption about the chemical nature of these interactions. To establish the stoichiometry of the reaction between TFV and (HСaf)3[PW12O40], electrochemical studies were conducted which showed that the activity of the radical is restored after exceeding the concentration ratio of 12 : 1, respectively. The synergism of the components of the compound (HСaf)3[PW12O40] is shown: when TFV interacts with H3[PW12O40], the maximum cathode current characteristic of TFV occurs at a concentration ratio of 4 : 1, respectively, while caffeine has no antiradical effect at all. Previously obtained data from X-ray diffraction analysis of compounds (HСaf)3[PMo12O40]∙6H2O, (HСaf)3[PW12O40]∙6H2O prove that the orientation of protonated caffeine relative to polyoxamethalate-anion is possible due to hydrogen bonds =O…H–N=. This process can result in the delocalization of the charge over the entire O-enriched surface, by all twelve groups [О–Ме–О]-, which are part of the POM, making the latter active centers capable of interacting with TFV. Therefore, the data presented correlate with the previously obtained results of spectrophotometric analysis and X-ray diffraction data and confirm the previously made conclusions.

Preparation of Hierarchical CuO Nanoparticles and their Photocatalytic Activity

2013 ◽  
Vol 785-786 ◽  
pp. 378-381
Author(s):  
Li Min Wang ◽  
Hong Ming Sun ◽  
Zhong Chao Ma ◽  
Ao Xuan Wang
Keyword(s):  
Cuo Nanoparticles ◽  
Formation Mechanisms ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
X Ray Diffraction ◽  
One Pot ◽  
Hierarchical Nanostructures ◽  
X Ray ◽  
Morphology And Structure ◽  
Scanning Electron

The uniform hierarchical and microspheric copper oxide (CuO) nanostructures, which have been successfully prepared via a simple one-pot method. The detailed morphology and structure of the synthesized hierarchical and microspheric nanostructures were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) and UVvisible spectroscopy. The morphology of CuO particles depends on the ammonium dihydrogen phosphate (ADP) used in the synthesis, the formation mechanisms were proposed based on the experimental results. The catalytic activity of as-synthesized CuO was demonstrated by catalytic oxidation of methylene blue in the presence of hydrogen peroxide (H2O2) and CuO with hierarchical nanostructures was found to be the best catalyst.

Initial formation mechanisms of (Ga1−xMnx)N nanorods grown on Al2O3 (0001) substrates

2008 ◽  
Vol 23 (12) ◽  
pp. 3275-3280 ◽  
Author(s):  
K.H. Lee ◽  
J.Y. Lee ◽  
H.C. Jeon ◽  
T.W. Kang ◽  
H.Y. Kwon ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Beam ◽  
Formation Mechanisms ◽  
X Ray Diffraction ◽  
Initial Formation ◽  
X Ray ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Xrd Patterns ◽  
Scanning Electron

The (Ga1−xMnx)N nanorods were grown on Al2O3 (0001) substrates by using rf-associated molecular beam epitaxy. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected-area diffraction pattern (SADP) results showed that the (Ga1−xMnx)N nanorods had (0001) preferential orientations. XRD patterns showed that the (Ga1−xMnx)N nanorods contained a small number of grains with different preferred orientations. High-resolution TEM (HRTEM) images showed that the (Ga1−xMnx)N nanorods consisted of different preferentially oriented grains. The initial formation mechanisms for the (Ga1−xMnx)N nanorods grown on Al2O3 (0001) substrates are described on the basis of the XRD, the TEM, the SADP, and the HRTEM results.

In Air Synthesis of Bi2S3 and PbS Microcrystals by Thermolysis of Single-Source Precursors

2009 ◽  
Vol 79-82 ◽  
pp. 1343-1346
Author(s):  
Zhen Ni Du ◽  
Yong Cai Zhang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Inert Gases ◽  
Formation Mechanisms ◽  
Single Source ◽  
X Ray Diffraction ◽  
Single Source Precursors ◽  
X Ray ◽  
Phase Pure ◽  
Scanning Electron

Without the protection of inert gases or vacuum environment, rod-like Bi2S3 and cubic-shaped PbS microcrystals were synthesized directly via pyrolyzing corresponding metal diethyldithiocarbamates in air at 300 °C for 3 h. The products have been characterized by X-ray diffraction and scanning electron microscope, and their possible formation mechanisms were also tentatively proposed. Furthermore, control experiments with multiple-source precursors revealed that our single-source precursors played an important role in preparing phase-pure Bi2S3 and PbS.

Structural and Electrical Characterization of the Initial Stage of Physical Vapor Transport Growth of 4H-SiC Crystals

2015 ◽  
Vol 821-823 ◽  
pp. 90-95
Author(s):  
Tatsuya Takahashi ◽  
Chikashi Ohshige ◽  
Noboru Ohtani ◽  
Masakazu Katsuno ◽  
Tatsuo Fujimoto ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Grown Crystal ◽  
Defect Formation ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Formation Mechanisms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Initial Stage ◽  
Crystal Seed

Defect formation during the initial stage of physical vapor transport (PVT) growth of 4H-SiC crystals in the [000-1] and [11-20] directions was investigated by x-ray diffraction, defect-selective etching, and micro Raman scattering imaging. X-ray diffraction studies showed that the growths in the [000-1] and [11-20] directions exhibited markedly different behaviors with respect to the defect formation during the initial stage of growth. While a characteristic lattice plane bending was observed for the PVT growth along [000-1], a tilted domain structure was revealed near the grown crystal/seed interface for the growth in the [11-20] direction. Micro Raman scattering imaging revealed that nitrogen enrichment occurred near the grown crystal/seed interface and was associated with compressive stress parallel to the interface. Based on the results, the defect formation mechanisms during the initial stage of PVT growth of 4H-SiC are discussed.

Squeezing out and Characterization of Silicon from Sand by Mg-Thermite Reduction Process

2020 ◽  
Vol 12 ◽  
Author(s):  
Md. Shoriful Islam ◽  
M. A. Sattar ◽  
M. A. Halim ◽  
Md. Asadul Hoque ◽  
Abdul Quader ◽  
...  
Keyword(s):  
Particle Size ◽  
Silicon Content ◽  
Chemical Nature ◽  
Low Cost ◽  
Reduction Process ◽  
Environmentally Benign ◽  
X Ray Diffraction ◽  
X Ray ◽  
Padma River

Background: Sand is one of the efficient sources of Silicon. We get quite easily the plethora of sand from the river side, Bangladesh. Utilization of the superfluous sand can be assisted to enhance our economy. Methods: In this work, silicon is extracted from sand by metal–thermite reduction process and the sample of sand is collected from padma river Rajshahi, Bangladesh. The process is environmentally benign and low cost. The reduction of the sand was performed with Mg powder, and purification was done by leaching out with HCl and HF. We have studied the structural properties, chemical nature and physical morphology. Results and conclusion: X-ray Diffraction (XRD) confirmed that the presence of elemental Si in the samples produced by Mg-thermite reduction process and the particle size was found 25.72±1.3 nm in an average. Surface morphology has been studied using Scanning Electron Microscopy (SEM) and the particle size seemed around 30 to 40 nm which was comparable to the obtained particle size from XRD. Fourier transform infrared spectroscopy (FTIR) showed the presence of Si-Si bonding in the investigating materials. The chemical nature of the sand has been studied by X-ray Fluorescence (XRF) analysis. Silicon content of sand was found about maximum 80%.

Growth Twins in YbxY1−xAl3(BO3)4 and NdxGd1−xAl(BO3)4 Crystals Observed by White-Beam Synchrotron Radiation Topography

1999 ◽  
Vol 590 ◽  
Author(s):  
X.B. Hu ◽  
J.Y. Wang ◽  
M. Guo ◽  
S.R. Zhao ◽  
B. Gong ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Formation Mechanisms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Black And White ◽  
White Beam ◽  
Structure Factors ◽  
Chemical Etch

ABSTRACTGrowth twins in Ybx Y1−xAl3(BO3)4 (YbYAB) and NdxGd1−xAl3(BO3)4 (NGAB) crystals were observed by white-beam synchrotron radiation topography combined with chemical etch. It was found that growth twins in YbYAB crystals are of inversion types in which two twinned pairs have the central inversion relationship. This kind of twinning was visible in x-ray topography not by ‘domain contrast’ but by ‘boundary contrast’ stemming from the kinematical x-ray diffraction at the boundary. Growth twins in NGAB crystals are of 1800 rotation types in which the twofold symmetric operation axis is parallel to the [0001] axis. This kind of twinning often shows black-and-white contrast in x-ray topography which originates from the different structure factors between twinned pairs. In addition. the formation mechanisms of growth twins are discussed.

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